This invention relates generally to an electronic calendar display device of the liquid crystal type and more particularly to a calendar display device where Sunday is always presented in the leftmost displayed column regardless of the calendar month and its starting day. A conventional electronic timepiece having a display used for displaying the calendar as a supplemental function has twenty-eight through thirty-one days located and displayed in fixed positions on the face of the timepiece. As indication of Sunday, for example, is displayed in an upper horizontal row, and the indication of Sunday is shifted laterally among the seven places representing the days of the week in a manner corresponding to the month being displayed. This embodiment is incorporated in the Seiko digital calendar watch Model M 354 produced by K. Hattori & Co., Ltd., Tokyo, Japan. In a normal printed calendar, Sunday is usually placed in the left column or occasionally, in Europe or America, in the right column. It is evident that a calendar may be more readily comprehended when Sunday is placed in the left column in a liquid crystal display. However, it is very difficult to display alternately seven date numerals in one date position on the calendar because it necessitates dividing the date display into many segments, and a great number of electrodes are necessary when it is considered that as many as thirty-one days need to be displayed. Therefore, as described above, the date numeral positions are fixed, and the day indication for Sunday is shifted laterally in the conventional calendar watch display of the prior art.
Another approach in the construction of a calendar display is shown in FIG. 1. The date numerals are visibly displayed in seven vertical columns even though the display panel has thirteen columns available. Thus, in any calendar week, there may be seven visibly displayed columns and a surplus of six columns of picture patterns which are not visibly displayed. When the number patterns of the left column n (FIG. 1) through the seventh column t from the left side are turned on, the display device shows a month in which the first day is on Sunday. During that month, the columns u-z are not turned on for display. When the number patterns of the second column o through the eighth column u from the left side are turned on, the display shows a month in which the first day is on Saturday. Columns n and v-z are not displayed. Similarly, when the number patterns of the seventh column t through the thirteenth column z are turned on, the display device shows a month in which the first day is on Monday. In this display construction, during each month, six columns of thirteen columns are entirely turned off, so that approximately half of the display face is blank. Thus, an unbalanced display configuration is presented, and the portion of the display panel driven for display in the current month is small and difficult to see and read.
What is needed is a calendar display device using liquid crystals which is simple in construction and displays each month in a large-sized format, with Sunday always appearing in the leftmost displayed column of the month.